- 著者
- Akiko Takatsuki-Hira Masahiro Kaketani Kohei Shimizu Takahito Tamura Takeshi Nakamura Yurika Toyama Takayuki Yoneyama Osamu Takeichi
- 出版者
- Nihon University School of Dentistry
- 雑誌
- Journal of Oral Science (ISSN:13434934)
- 巻号頁・発行日
- pp.20-0543, (Released:2021-02-17)
- 参考文献数
- 40
Purpose: This study aimed to examine novel techniques using prototype endodontic obturators to obturate a resin-based sealer.Methods: Powder-liquid ratios of MetaSEAL Soft were changed to obtain suitable root canal sealing, and the physical properties for various powder-liquid ratios were analyzed according to ISO-6876. Tensile bond strength was also examined. Prototype endodontic obturators with a combination of thread numbers and pitch angles were analyzed for sealing ability after MetaSEAL Soft was obturated in simulated root canals.Results: Powder-liquid ratios of 1.0:1, 1.1:1, 1.2:1, and 1.3:1 showed suitable physical properties; however, flow for 1.4:1 was below a standard value. Tensile bond strength increased gradually when the powder-liquid ratio changed from 1.0:1 to 1.3:1, and 1.3:1 and 1.4:1 showed the highest and lowest bond strengths, respectively. Sealing ability increased when pitch angles of the obturators were 5°, 8°, and 11°; 11° showed the best results. Similarly, sealing ability increased when the thread number was 12, 17, and 22 pitches; 22 showed the best results.Conclusion: These findings suggest that the prototype endodontic obturator can be useful for obturating MetaSEAL Soft, and a powder-liquid ratio of 1.3:1 MetaSEAL Soft may be the most suitable for achieving excellent sealing.
- 著者
- Hiroki Komiya Kohei Shimizu Kae Ishii Hiroshi Kudo Teinosuke Okamura Kohei Kanno Masamichi Shinoda Bunnai Ogiso Koichi Iwata
- 出版者
- Nihon University School of Dentistry
- 雑誌
- Journal of Oral Science (ISSN:13434934)
- 巻号頁・発行日
- vol.60, no.4, pp.493-499, 2018 (Released:2018-12-27)
- 参考文献数
- 23
- 被引用文献数
- 28
Pulpitis often causes referred pain in opposing teeth. However, the precise mechanism underlying ectopic pain associated with tooth-pulp inflammation remains unclear. We performed the present study to test the hypothesis that functional interactions between satellite glial cells (SGCs) and trigeminal ganglion (TG) neurons are involved in ectopic orofacial pain associated with tooth-pulp inflammation. Digastric muscle electromyograph (D-EMG) activity elicited by administration of capsaicin into the upper second molar pulp (U2) was analyzed to evaluate noxious reflex responses. D-EMG activity was significantly increased in rats with lower first molar (L1) inflammation relative to saline-treated rats. Significantly increased expression of glial fibrillary acid protein (GFAP), a marker of activated glial cells, and connexin 43 (Cx43), a gap-junction protein, was observed in activated SGCs surrounding U2-innervating TG-neurons after L1-pulp inflammation. Daily administration of Gap26, a Cx43-inhibiting mimetic peptide, into the TG significantly suppressed capsaicin-induced D-EMG activity enhancement and reduced the percentage of fluorogold-labeled (U2-innervated) cells that were surrounded by GFAP-immunoreactive (IR) and Cx43-IR cells after L1-pulp inflammation. These findings indicate that tooth-pulp inflammation induces SGC activation and subsequent spread of SGC activation in the TG via Cx43-containing gap junctions. Thus, remote neuron excitability becomes enhanced in the TG following tooth-pulp inflammation, resulting in ectopic tooth-pulp pain in the contralateral tooth.
- 著者
- Tetsuro Watase Kohei Shimizu Hiroki Komiya Kinuyo Ohara Koichi Iwata Bunnai Ogiso
- 出版者
- Nihon University School of Dentistry
- 雑誌
- Journal of Oral Science (ISSN:13434934)
- 巻号頁・発行日
- pp.16-0854, (Released:2018-02-26)
- 参考文献数
- 21
- 被引用文献数
- 9
A study was conducted to evaluate the mechanisms underlying ectopic orofacial pain associated with tooth pulp inflammation in rats. We observed a significant decrease in the head withdrawal threshold (HWT) response to mechanical and heat stimuli applied to the ipsilateral facial skin upon application of complete Freund’s adjuvant (CFA) to the upper first molar (M1TP) in comparison to application of vehicle. A large number of trigeminal ganglion (TG) neurons showed transient receptor potential vanilloid 1 (TRPV1) immunoreactivity (IR), and some of them were retrogradely labeled with fluorogold injected into the facial skin. A large number of cells showing IR for glial fibrillary acidic protein (GFAP) were observed in the 2nd compared to the 1st or 3rd branch regions of the TG, and TG cells innervating the facial skin were also surrounded by GFAP-IR cells. After administration of TRPV1 antagonist into the facial skin of M1TP CFA-treated rats, the decrease of HWTs in response to mechanical and heat stimulation of the facial skin was significantly reversed. The present findings suggest that the excitability of TG neurons is enhanced upon tooth pulp inflammation, leading to overexpression of TRPV1 in TG neurons innervating the facial skin, and that satellite glial cells are also activated, resulting in the development of ectopic orofacial pain.